diff --git a/controllers/util.go b/controllers/util.go
index b7c8401c..e2333405 100644
--- a/controllers/util.go
+++ b/controllers/util.go
@@ -17,6 +17,7 @@ package controllers
 import (
 	"fmt"
 	"strconv"
+	"strings"
 
 	"github.com/casdoor/casdoor/conf"
 	"github.com/casdoor/casdoor/i18n"
@@ -56,7 +57,7 @@ func (c *ApiController) T(error string) string {
 // GetAcceptLanguage ...
 func (c *ApiController) GetAcceptLanguage() string {
 	lang := c.Ctx.Request.Header.Get("Accept-Language")
-	if lang == "" {
+	if lang == "" || !strings.Contains(conf.GetConfigString("languages"), lang[0:2]) {
 		lang = "en"
 	}
 	return lang[0:2]
diff --git a/i18n/util.go b/i18n/util.go
index 8bee7885..b0ec9c73 100644
--- a/i18n/util.go
+++ b/i18n/util.go
@@ -17,7 +17,6 @@ package i18n
 import (
 	"embed"
 	"fmt"
-	"log"
 	"strings"
 
 	"github.com/casdoor/casdoor/util"
@@ -27,10 +26,7 @@ import (
 //go:embed languages/*.ini
 var f embed.FS
 
-var (
-	langMapConfig  = make(map[string]*ini.File)
-	isNotFirstLoad = make(map[string]bool)
-)
+var langMapConfig = make(map[string]*ini.File)
 
 func getI18nFilePath(language string) string {
 	return fmt.Sprintf("../web/src/locales/%s/data.json", language)
@@ -77,16 +73,14 @@ func applyData(data1 *I18nData, data2 *I18nData) {
 func Translate(lang string, error string) string {
 	parts := strings.Split(error, ".")
 	if !strings.Contains(error, ".") || len(parts) != 2 {
-		log.Println("Invalid Error Name")
-		return ""
+		return "Translate Error: " + error
 	}
 
-	if isNotFirstLoad[lang] {
+	if langMapConfig[lang] != nil {
 		return langMapConfig[lang].Section(parts[0]).Key(parts[1]).String()
 	} else {
 		file, _ := f.ReadFile("languages/locale_" + lang + ".ini")
 		langMapConfig[lang], _ = ini.Load(file)
-		isNotFirstLoad[lang] = true
 		return langMapConfig[lang].Section(parts[0]).Key(parts[1]).String()
 	}
 }
diff --git a/web/src/Setting.js b/web/src/Setting.js
index 87455107..016305e2 100644
--- a/web/src/Setting.js
+++ b/web/src/Setting.js
@@ -553,6 +553,9 @@ export function setLanguage(language) {
 }
 
 export function getAcceptLanguage() {
+  if (i18next.language === null || i18next.language === "") {
+    return "en;q=0.9,en;q=0.8";
+  }
   return i18next.language + ";q=0.9,en;q=0.8";
 }